RNA interference is a technology of gene silencing mediated by double-stranded small interfering RNA (siRNA) composed of about 20 nucleotides or more. It has sequence specificity, so the small nucleic acids based on RNA interference has a great application prospect in disease treatment. However, as the molecules of small nucleic acids, including siRNA, don't have the ability to target tissues or cells, have a poor ability to penetrate cell membrane and are extremely unstable in a physiological environment, their delivery system, vector in particular, is a key issue that should be solved urgently. It is also one of the most critical factors deciding whether small nucleic acid drugs can eventually and successfully be used in clinic. At present, the small nucleic acid drugs used to treat solid tumors are under clinical trial in the world, for example: TKM-D80301 developed by Tekmira, ATU027 developed by Silence Therapeutics, and CALAA-01 developed by Calando Pharmaceutics.
Therefore, it is very important to develop delivery system and preparation of small nucleic acids with high biocompatibility, and low cytotoxicity and side effects to treat diseases.